The National Association for the Advancement of Coloured People in Maryland will launch a series of radio adverts on Tuesday, urging voters to support equal marriage for same-sex couples in the state referendum on 6 November.

The adverts feature former NAACP national chairman, Julian Bond, who says that voting in favour of equal marriage is “the right thing to do.”

“I know a little something about fighting for what’s right and just,” he says, “Maryland’s gay and lesbian families share the same values, and they should share in the right to marry.”

He also says that the issue of equal marriage is not primarily a religious one:

“I believe people of faith understand this isn’t about any one religious belief – it’s about protecting the civil right to make a lifelong commitment to the person you love,”

According to the NAACP, the oldest civil rights group in the US, the adverts will air in Baltimore and Washington, and are aimed at key demographics, and have been timed to air a month ahead of the vote on the issue.

A bill to legalise same-sex marriage in Maryland was passed by the Maryland General Assembly in February 2012 and signed into law on 1 March 2012, by Governor Martin O’Malley.

However, opponents of marriage equality successfully gathered signatures to force a referendum on the decision.

Opponents have produced a new campaign video that has been shown on state television, which urges residents to vote against Question 6 and says: “Everyone is entitled to love and respect, but no one is entitled to redefine marriage”.

The NAACP, based in Baltimore, endorsed equal marriage for gay people, back in May, but US Republican presidential candidate Mitt Romney told the annual NAACP convention in July that he would oppose marriage equality.